NPR: the serotonin "hypothesis" takes another hit

Howard Brody at Hooked links to a report on NPR about the chemical-imbalance explanation for depression and how it lacks empirical support. They’re very late in coming, but I’m glad more of these stories are appearing, since it annoys me to no end that people who should know better continue to peddle this story in the media (all while their counterparts deny that anyone really believes it).

Brody is disappointed that they didn’t talk to Lacasse and Leo (they could have talked to Irving Kirsch as well), but the people they did interview were reasonably clear about the fact that that the monoamine story is a myth. I’m not thrilled about the impression the report gives to some extent (especially in the misleading title, “When It Comes to Depression, Serotonin Isn’t the Whole Story”) – that this explanation is merely reductionistic or incomplete rather than flat wrong. But the basic message is there.

I also agree with Brody that it’s odd, and to me comes across as seriously naïve, that the report doesn’t talk about the role of the pharmaceutical companies (with the complicity of the FDA) in promoting this myth. It hasn’t been so successful and enduring simply because people like the certainty of simplistic explanations that promise a cure. It’s been so successful and enduring because there are billions of dollars in profits at stake for the makers of psychotropic drugs, and they have no interest in the public becoming aware that the conception of disease and mechanism of action their product is based on is a myth.

I’m slightly disturbed by the focus on the alleged positive and negative consequences of the neurotransmitter story. Alan Frazer, interviewed for the report, claims that the story is positive in that it allegedly “enables many people to come out of the closet about being depressed,” although he offers no evidence in support of this position (the evidence suggests that rather than having a destigmatizing effect, biological explanations are themselves stigmatizing). Pedro Delgado

points out that years of research have demonstrated that uncertainty itself can be harmful to people — which is why, he says, clear, simple explanations are so very important.

"When you feel that you understand it, a lot of the stress levels dramatically are reduced," he says. "So stress, hormones and a lot of biological factors change."

No evidence of this is provided, either, but the paternalism is shocking. It is completely unethical for doctors to knowingly lie to patients about the nature of their condition, or for scientists to lie to the public.*

The report does mention some drawbacks: that people are led to take medications rather than using talk therapy, and that it distracts researchers from studying “other” causes of depression. Both of these are understated, but the point isn’t that they overstate possible benefits of perpetuating this myth and minimize the harms, even though they do. The problem is that they’re focusing on the supposed effects of telling a false tale rather than the fact that it is false. Even in the hypothetical case that lying to depressed people making decisions about treatment and to the public about a major health issue had nothing but benefits, it would still be wrong to do. And this hypothetical situation not only doesn’t apply, but it couldn’t possibly. Creating a culture in which scientists, physicians, and counselors accept and perpetuate falsehoods will always cause harm in the long term.

*And this emphasis on simplicity evades the central issue. As Lacasse and Leo argue:

Since 2002, the first author (JRL) has repeatedly contacted the FDA regarding [the use of the serotonin myth in drug advertising]. The only substantive response was an E-mail received from a regulatory reviewer at the FDA: “Your concern regarding direct-to-consumer advertising raises an interesting issue regarding the validity of reductionistic statements. These statements are used in an attempt to describe the putative mechanisms of neurotransmitter action(s) to the fraction of the public that functions at no higher than a 6th grade reading level” (personal communication, 2002 April 11).

It is curious that these advertisements are rationalized as being appropriate for those with poor reading skills. If the issues surrounding antidepressants are too complex to explain accurately to the general public, one wonders why it is imperative that DTCA of antidepressants be permitted at all. However, contrary to what the FDA seems to be implying, truth and simplicity are not mutually exclusive. Consider the medical textbook, Essential Psychopharmacology, which states, “So far, there is no clear and convincing evidence that monoamine deficiency accounts for depression; that is, there is no ‘real’ monoamine deficit” [44]. Like the pharmaceutical company advertisements, this explanation is very easy to understand, yet it paints a very different picture about the serotonin hypothesis.